Proton density (PD) MRI: when it beats T2
PD shows cartilage, menisci and ligaments with good signal. This is when to choose it, and the magic angle trap that comes with it.
Proton density (PD)
Signal follows the number of protons: fluid and cartilage bright to intermediate, menisci, ligaments and tendons dark.
The joint sequence: high SNR and sharp detail for menisci, labrum, ligaments and cartilage. With fat suppression it also shows marrow edema.
Short TE brings magic-angle signal into tendons, and a long echo train blurs it.
This page is one entry from the MRI Technologist Reference
The full reference has 31 protocols, 9 dynamic study timelines, 19 artifacts, 16 scanner problems and 15 safety topics, as a PDF in English and Arabic plus an interactive tool.
Educational reference. It does not replace your site protocols, the radiologist's instructions, the MR safety officer, or the manufacturer's instructions for any implant, device or contrast agent. Parameter values are typical starting points at 1.5 T and must be adapted to the scanner, coil and patient.